This invention relates to a novel electric motion platform and control system for controlling movement of the same. More specifically, this invention relates to an electric motion platform for simulating real world motion under direction of a computer or other external device.
Motion platforms may be found in both military and commercial environments, for example in flight simulators, coin-operated entertainment rides, medical research, and, more recently, virtual reality machines. In a typical application, one or two person module, such as a simulated xe2x80x9ccockpitxe2x80x9d in a flight training system, is mounted to the motion platform. As the user watches screens displayed in the module, the platform moves so that the user experiences true-to-life motion cues. Motion platforms for commercial flight simulation are designed for accuracy and, consequently, are quite expensive.
Conventional motion platforms that attempt to simulate real world motion suffer several drawbacks. The motion platforms are complicated in structure, having many distinct moving parts, and thus are expensive to manufacture and maintain. In addition, the movement of the motion platform is somewhat restricted. Conventional motion platforms undergo what is referred to as quadrature motion, driven by a motor and a pair of arms, one of which is connected to the platform. In these conventional motion platforms, as exemplified in FIG. 2A, arms 200 and 202 are connected to a motor box 204 that rests on a platform base 204. Arm 202 connects to a corner of the platform (not shown), and an identical motor and arm assembly is at an opposite corner of the platform. As is evident from the figure, the movement of arm 200 in a downward direction is limited by the base, with the result that the maximum angular deflection of the platform is that which results from motion of the arms over a single 90xc2x0 arc or quadrant in the direction of arrow A. Movement of the motion platform itself thus is usually restricted to about xc2x115 degrees from a plane parallel to the ground surface.
Another disadvantage of conventional motion platforms is that, because of the 90xc2x0 orientation of the arms at the start position, the motor is at its highest load when started. Accordingly, these platforms require large, heavy motors, which are both heavy and costly. While weight and cost may not be significant factors for custom designed motion platforms used for military or high-end commercial applications; they have limited the application of such platforms in entertainment and other potential commercial applications.
Further, the prior art motion platforms are relatively large and occupy lots of floor space. This is undesirable where it is desired to offer a selection of games, each mounted on its own motion platform. The size and weight of these bulky platforms makes then difficult and expensive to ship and install.
Conventional motion platforms generally suffer from another drawback in that the structure is relatively tall to accommodate the complex and sizable motors, control linkages and electronics of the overall system. This requires the passenger module to be mounted high above the floor, necessitating that the xe2x80x9criderxe2x80x9d climb up into position. Climbing into an elevated user module is awkward and presents a safety risk often requiring a trained operator to be present during operation.
For these and other reasons, the motion platforms heretofore available have not proven to be entirely satisfactory and have not been fully suitable for practical application to the entertainment industry and to other commercial applications in which cost, size, convenience, safety, adaptability and ease of use are important factors.
Accordingly, it is therefore a general object of the present invention to provide a motion platform and control system for controlling movement of the same which will obviate or minimize difficulties of the type previously described.
It is a specific object of the invention to provide a general purpose, digitally controlled motion platform and associated control system that has a wide variety of applications.
It is another object of the invention to provide a motion platform that has relatively few moving parts and is relatively lightweight and compact.
It is still another object of the invention to provide a motion platform that offers a range of motion of up to xc2x135 degrees from level.
It is yet still another object of the invention to provide a motion platform that occupies a relatively small amount of floor space.
It is a further object of the invention to provide a motion platform that has a seat portion relatively close to the ground so that a user can easily climb into and exit a user module mounted on the motion platform without the assistance of a trained operator.
It is yet a further object of the invention to provide a motion platform that only needs a relatively small motor to operate.
It is still a further object of the invention to provide a motion platform that may be mass-produced at relatively low cost.
It is yet still a further object of the invention to provide a control system for a motion platform that enables real time monitoring of movement of the motion platform and reaction to that movement.
A preferred embodiment of the invention which is intended to accomplish at least some of the foregoing objects includes a motion platform comprising a base, a top, and a support member for supporting the top relative to the base. The motion platform also has a pair of positioning motor assemblies mounted to the base and an arm assembly extending between each of the positioning motor assemblies and the top of the platform. The arm assemblies are responsive to rotary motion of a respective one of the positioning motor assemblies and are adapted to rotate 360 degrees about the respective positioning motor assembly. The motion platform further includes a microcontroller electrically connected to the positioning motor assemblies for controlling rotational speed and rotational direction of the positioning motor assemblies and thus angular displacement of the top of the motion platform relative to the base. The motion platform has two degrees of freedom, pitch and roll.
The base and the top of the motion platform may be constructed of any suitable material and are preferably composed of an aluminum alloy. The base and the top are also preferably one-piece frames of a rectangular configuration.
The motion platform may also have solid state relay and delay circuitry electrically connected between the positioning motor assemblies and the microcontroller to allow relatively instantaneous reversal of direction of rotation of the positioning motor assemblies. The motor assemblies are mounted above the base of the motion platform so that the arm assemblies may be rotated over a full 360-degree arc.
Each positioning motor assembly preferably includes a positioning motor and a reducer gear. The reducer gear is coupled between a respective arm assembly and positioning motor. Each arm assembly preferably includes a rotating arm for connection at one end to an output shaft of the reducer gear, a connecting arm linking the platform top to the rotating arm, and a joint for coupling the rotating arm to the connecting arm to allow angular displacement of the connecting arm relative to the rotating arm. When the top is at a start or level position, the rotating arm and connecting arm form an obtuse angle, requiring less start-up work by the motor.
The arm assembly is mounted between the positioning motor assembly and the platform top to displace the top up to xc2x135 degrees from an imaginary plane level with a ground surface.
The motion platform may further include first sensors for detecting when an arm assembly is in a home, position and second sensors for sensing the speed and amount of rotation of each of the positioning motors. The second sensors detect passage of the fan blades of the motor assemblies to monitor both speed and amount of rotation.
A control system for controlling movement of motion platform in accordance with the present invention includes a power supply and a microcontroller having an input, an output, and a memory. At least two positioning motors are electrically connected to at least two solid state relays electrically connected to the output of the microcontroller. A first set of sensors detects when the connecting arms of linkage assemblies between the base and the top of the platform are in a predetermined home position, and a second set of sensors determines the speed and extent of rotation of each of the positioning motors. The microcontroller controls the speed and direction of the positioning motors based on command signals input into the microcontroller. The sensors may be of any suitable type but preferably comprise LEDs and photo-transistors.
A method for controlling movement of a motion platform includes the steps of: initializing the motion platform so that a top of the motion platform is level; receiving data input into a data entry unit, the data being converted into signals for controlling activation, speed, and direction of rotation of positioning motors for positioning the motion platform; activating the positioning motors in response to the received data; and when the positioning motors are activated, moving the positioning motors in a specific direction and at a specific speed in response to the received data to orient the motion platform. The data entry unit receives at least one of real-time data or predetermined data.
Additional objects and advantages of the invention will be apparent to those of ordinary skill in the art from the following description of a preferred embodiment, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out in the appended claims.